Tire trimmer



May 6, 1930- v c. EMAYNARD 1,757,127

TIRE TRIMMER .Filed Aug. 10. 1928 l INVENTOR. E'f-/A NLES 275m? MAY/VAUD.

A TTORNE Y.

A Patented Mays,Y `193() A' UNITED STATES CHARLESEDGAR'MAYNARD, 0F NoRTi-IAMPTON,MAssAci-IUSETTS, Assis-NOR To RISK RUBBER COMPANY, or onrcorna FALLS, ivrAssAmans nfrfrs,AcomoRATIolst'` or' MASSACHUSETTS TIRE TRifriyruRV v Appiieati'on filed August 10, i'e'asfsriai m1295338.

My invention relates to a device :for trimming the edges of treadlstock or sidewall strips after this stock has been stitched to aV tire carcass.

The purpose of my inventionfis to provide a device that will yaccurately and essentially.

automatically turn the edges of such strips and that may easily and quickly be brought into Working position from an inoperative position. Another purpose of my invention is to provide a device that vvill'cons-tantly hold the'trimmer against the tire with a yield-k ing pressure. Other purposesy will be apparent from the following specification and claims. Y

Referring to the drawings showing but one embodiment of my invention:

Fig. 1 is a front elevation lof the trimmers mounted on the frame of a tire building machine; Y

A Fig. 2 isa view taken substantially on line 2--2ofFig.1; i

Fig. 3 is an enlarged View of .one of the trimmers showing it in trimming position; and

Fig. 4 is a view taken substantially-on line 4-4 of Fig. 3.

In the drawings a tire carcass 'has been constructed on a tire building drum- 11 and a tire `tread 12, built in-this case as one unit with the sidewall strips, has been located and stitched onto the carcass 10.. A pair of trimmers, one for each edge of the drum, are carried by a bar 13 fixed to a-member 14 that is pivoted on a shaft 15 carried by a bracket 16 on the housing of a tire building machine 17. A stop 18 (zo-acting With an adjustable bolt 19 on the member 14 regulates the horizontal position of the'y bar 13 While a stop plate 20 allows the bar 13, together 'with the trimmers, to be tilted back intoan inoperative position as indicated bythe dotted lines 21.

As the trimmers are similar only one Will be described, this description suiicing for both units. port bracket 22 slidably `mounted ony the bar 13 and prevented from rotation by ka pair ot' keys 23. A knife holder, 24 is pivotally held on a stud 25 adjustably xed in an elongated slot 26 in the bracket 22. A knife blade27 The trimmer consists of a supis clamped-'onto a ecting portion 28 of'fth'e holder 24'.v A tension spring 29 `fliedib'etvveer'l afpoint on`the1holder'24 and on theb'racket 221tends lto keep the holder against a flange A f 30 onfthe bracketV 22 as shovvnv in Fig. 2.

A vlink 31C is pivotedtothe -stud125 and a' coiled spring 32, fitting at one endl 33 linto the studl` 25,- is-'fastened tofthe link31 as at- 34 (see 4). Normally the link'31'will restas shown in Fig. 2 Without much or any tension on theV spring 32 against the portionl `fHowever,vvhen it is'desiredtoii'nove the blade 26toward the tire (see Fig; 3)'`the link 31'is movedvbackso that aplunger3 5,carried bytheflinkand control-led bya knobf364 andk a spring "37, will engage behind-a handle 38 ofthe holder 24. Thelinks"mov`ement,'of`

approximately'120", 'v vill put a tens-ion-A on the spr1ng32 and rotate 'thelink-ab'out the stud 25-until the lbladef27 comes in Contact with "i the tire,`fthe bladethen-riding at this point f With-a'yieldable pressure.,

^ The'trimmers 'may be adj usted for' various' Width drums-bymoving them-along the bar 13 and locking them-in place by-a set screw 39. The bar itself; may'bemoved 'avvay or-v toward the drum-by moving the shaft 15in thebracket 16.

The operation offthetrimmers `is l-a's follovv. The tirecarcass lO'is firstconstructed on thebuildingdrum lland the ltiretread 12, made 'eitherfseparate'oi integral/'With sideivallfstrlps,I `is stitched into place von the carcass. Thel` b ar13is brought down from the inoperative-position21to' a 'positionVv int front of. thek drum as shown in Figs. 1 andV 2. The operator then locks the links 31 in back of the 'handles38 with the plungers 35 as shown in Fg.`3 and rotates the drum.: As vthe drum rotates theblades 27 Will gradually cut or force their Way through the rubber stock at kthe predetermined point at which the blades Were set. The pressure caused by the springs 32 is not great enough to cause the blades to cut throughmore than just the rubber stock.

When `the blades f have performed their func-k tion,' the operator lifts up on the knobs 36 which kallows the springs 29 todraW the holders 24'back against the flanges 30. The cut blade, a stud adapted to act as a pivot-for the holder, and a spring controlled member also oil strips of rubber 40 arethen pulled olf the i tire by the operator.v v

During the time the blades are cutting their Way through the rubber the machine operator is free to gather his material for the next tire. Y

Having claim: Y, Y

1'. In a machine of the character described,

a trimming unit adapted to be positioned ad`V jacent a tire buildingfdrum,"rsaid unitcomprising 'a blade, a holder for carrying the carried by the stud adapted to be locked behindthe holder to. thereby :forceV the saidV bladefinto yielding contact With the tire..

2. In, y a tire building ,Y machine, a device ortrimmingsurplus rubber stock from tire casings comprising a bracket mounted kadjacent a tire buildingk drum,`a studadjustably Xed tothe bracket, a blade'adapted, when i pressed into contact with the rubber stock on a tireecasing on the building drum, to gradf ually'cut its Way through the rubber stock,

a blade holder pivoted on the stud and nor. i

mally holding the blade from Contact `With the tirecasing anda spring pressed member also carried by the said stud to holdthe blade in yielding contact with `thetirev when the said spring pressed member is locked behindv the blade holderfV j ,c 3. In' a'tire buildingmachine, a pair of de-V Vices for trimming surplusrubber stock fromV tire casings each comprising 'a bracket mounted adjafent one side of a tire building drum, a stud adjustably fixed to each bracket, a pair of blades adapted, when pressed into Contact with the rubber stock on a tire casing on the'building drumyto gradually cut theirrwayfthrough therubber stock, blade holders pivoted on the studs andinormallyY holding the blades from Contact with the tire casingjand'spring pressed members also carried by the studs to hold the blades in yielding contact With the tire When the said spring. pressed members are locked behind the'blade holders, each device adjusted and operable Y independent of the other.

thus described `my invention, I 

